Brock Motum and Mike Ladd are gone, making DiIorio and D.J. Shelton the old men of the team.
"Coaches keep telling me it's my team now," DiIorio told Cougfan.com this week.
DiIorio's street cred for the role is undeniable. He truly worked his way up from the bottom, coming in as a walk on in 2009-10 and earning playing time in 21 games that season courtesy of major-league diligence and a devotion to defense.
"He's one of those kids that you never have to tell something more than once," says head coach Ken Bone. "Will is a very mature and disciplined young man ... He's not the raw-raw, vocal leader but does an excellent job of leading by example and being a great role model."
Even before coaches talked with him about his leadership role, DiIorio said new players, upon their arrival on campus last month, approached him with questions about basketball and school generally.
"I love that (the young players) put the responsibility on me because I was hoping I would have that role this year," DiIorio said. "When things get emotional on the floor, they'll turn to me.
DiIorio said Bone has asked him to mentor all the youngsters, not just the rookies. So Que Johnson, who redshirted last season as a true freshman, also will be under DiIorio's watchful eye. And he sees big things in the offing for the touted shooting guard.
"Boy, he's a great scorer," said DiIorio of Johnson. "He's a really hard to guard, he does a lot with the ball."
DiIorio said he's steadily grown into a leader over the years and that the examples set by former teammates Marcus Capers and Abe Lodwick helped guide him.
"Those guys were great role models," DiIorio said. "They made it an easy transition when I was a freshman. I'm going to try to be like them. They helped me out a lot."
As a true freshman, DiIorio said he was apprehensive -- hesitant at best. He didn't want to get in anyone's way or step on anyone's shoes. He knew he wasn't going to be relied on for much coming off the bench, so he focused on defense.
Lots of defense.
"My first year, not all my confidence was out there," DiIorio said. "I thought defense was really something I needed to master if I ever wanted to play."
He didn't do much in the stat box that season, or the following one, but he was a highlight reel of the intangibles.
Loose balls, boxing out, perimeter defense -- DiIorio was making a mark.
Then last season he became mainstay in the rotation, playing in 30 games and starting three of them.
His goal for this season is lofty: Help get the Cougs to the NCAA Tournament. After that, he has his eyes set on playing professionally overseas.
He notes that he's majoring in strategic communication with an emphasis in public relations. "If I can't play ball, it's time to step into the real world," DiIorio said. "Would love to get to work overseas in some capacity."
DiIorio led WSU in FG percentage last season, hitting 35 of 64 shots.